Preface

Preface

Broadband digital communication used to be limited only to backbone network infrastructure and to private transmission facilities of large corporations. Digital broadband access to average households had been promoted for video-on-demand applications and succeeded, most recently, only as a fast Internet extension. At this writing, there are at least 15 million homes with PCs connected to the Internet through broadband access networks in forms of either ADSL or cable modem. Networking PCs through a home router, with a home network at one side and the broadband access modem at the other side, is a good way to share the Internet access among multiple PCs and their users. Many network service providers, such as AT&T Media One, have endorsed such an approach rather than insisting that customers pay more for multiple IP addresses. There are many different brands of home routers available on the market with many varieties of home networking capabilities.

A home network system can be based on a few transmission media and many existing and emerging standardized communication protocols are available. A home network system can be based on in-house telephone wiring, TV coaxial cable, existing power line, or radio frequency for wireless. Over the telephone wiring, standards (HomePNA 1.0 and HomePNA 2.0) have been developed by the HomePNA industry consortium. Using power line, a standard called HomePlug is now finalized by the HomePlug group. For radio frequency wireless communication systems, protocols (SWAP 1.0 and SWAP 2.0) are produced by the HomeRF committee. These are a few of the emerging transmission systems that have been developed on the concept of no new wire for existing home applications. Transmission throughputs of these systems are between 1 and 30 megabits per second (Mbps). They are also developed with multimedia content in mind. Many of them can carry voice or music packets with guaranteed quality of service. For newly constructed homes, Category 5 twisted pair cable can be installed in a home run or star configuration to take advantage of Ethernet standards at transmission throughputs of 10 Mbps, 100 Mbps, or even 1 gigabit per secopnd (Gbps) for PC interconnection and sharing Internet access. Wireless Local Area Network (LAN) technology defined by IEEE 802.11, IEEE 802.11a, and IEEE 802.11b can also be used in the home data networking environment.

Meanwhile, household electronics are more oriented toward digital contents such as MP3 for music, DVD for video, and high-definition TV. Home networking can be useful for the distribution of digital multimedia content among a central and/or a few displaced resource centers and many presentation devices. A PC can be used as a resource center, a presentation device, or both. The use of a digital home network can also be extended to cover home automation applications. Using X-10 or CEBus-based devices, hobbyists have looked into many scenarios to make life easier and more enjoyable. The incorporation of a high-throughput home network and Internet to these schemes could eventually make them move into a mainstream market. Home appliance manufacturers would also like to see their products connected online for providing real-time maintenance and other value-added applications. Among many great possibilities, home data networking is taking the lead.

To understand home network systems, we first examine transmission potentials for the previously mentioned communication media in terms of channel and noise models. This leads to calculations of channel capacities for these diverse transmission environments. The channel capacity is the limit of what a transceiver can achieve. By comparing channel capacity with the transmission throughput of a particular home network system, we can understand why certain signal processing or coding techniques are necessary and if any further improvements can be made. We then look into each applicable communication protocol individually. For each protocol, we will study key features of related standards and corresponding implementation approaches in enough detail that a person, with some effort, can gain a good grasp of the subject. This book can be a general reference for people interested in the technical details of home networking transmission systems. More importantly, this book provides a condensed resource in terms of systems engineering and technology merits for engineers and students to carry on related research and development activities. Understanding can be achieved through not only reading but also practicing computer simulation using the MATLAB files and Simulink models on the Prentice Hall companion Web site, http://authors.phptr.com/chen/. The MathWork also has a central site where you can find the book's electronic files: http://www.mathworks.com/matlabcentral/fileexchange/